It is known that “top loading” washing machines are devices with a top door that includes a tub, a basket and an agitator or “impeller”, mounted on a vertical shaft. Most models of “top loading” washing machines have a vertical shaft that is coupled to a drive system consisting of a motor, transmission (gearbox) and clutch.
In general, the clutch work of a washing machine is that of allowing the motor and the transmission to operate, as programmed, within certain variations in the output rotational speed of the vertical shaft, to which the agitator and basket are bound in order to carry out, on its program, the washing operation, i.e., the oscillating movement of the agitator in relation to the basket, and where soap and water are stirred between fabrics, removing the dirt from them. After some periods of stirring, the agitator and basket are stopped, which allows the washing water to be drained, so that in a final operation the agitator and basket are driven in a manner that they spin together, and at high speed, characterizing the operation of centrifugation that expels the excess water retained in clothes and fabrics.
Most of conventional clutches use a gear mechanism and springs for changing the transmission of the motor power between the washing and dewatering steps. The conventional clutch springs provide a way of carrying out power transmission among the motor and the agitator and the basket.
Each conventional clutch spring requires high precision in their laps, and depends on calculations relating to its inner diameter, among others. In addition, to control the movement of the clutch springs, electro-magnet, actuators, lever arms and other components are required. Therefore, the conventional clutch mechanism has a complicated construction, resulting in an increased production cost.
Currently there are several types of clutches for different types of “top loading” machines and most of them are somewhat complex, even for simpler applications.